Add custom types, version command, and restore --verify flag

- Add internal/types package with type-safe wrappers for IDs, hashes,
  paths, and credentials (FileID, BlobID, ChunkHash, etc.)
- Implement driver.Valuer and sql.Scanner for UUID-based types
- Add `vaultik version` command showing version, commit, go version
- Add `--verify` flag to restore command that checksums all restored
  files against expected chunk hashes with progress bar
- Remove fetch.go (dead code, functionality in restore)
- Clean up TODO.md, remove completed items
- Update all database and snapshot code to use new custom types

internal/snapshot/snapshot_test.go

@@ -101,7 +101,7 @@ func TestCleanSnapshotDBEmptySnapshot(t *testing.T) {
 		config: cfg,
 		fs:     fs,
 	}
-	if _, err := sm.cleanSnapshotDB(ctx, tempDBPath, snapshot.ID); err != nil {
+	if _, err := sm.cleanSnapshotDB(ctx, tempDBPath, snapshot.ID.String()); err != nil {
 		t.Fatalf("failed to clean snapshot database: %v", err)
 	}
 
@@ -119,7 +119,7 @@ func TestCleanSnapshotDBEmptySnapshot(t *testing.T) {
 	cleanedRepos := database.NewRepositories(cleanedDB)
 
 	// Verify snapshot exists
-	verifySnapshot, err := cleanedRepos.Snapshots.GetByID(ctx, snapshot.ID)
+	verifySnapshot, err := cleanedRepos.Snapshots.GetByID(ctx, snapshot.ID.String())
 	if err != nil {
 		t.Fatalf("failed to get snapshot: %v", err)
 	}
@@ -128,7 +128,7 @@ func TestCleanSnapshotDBEmptySnapshot(t *testing.T) {
 	}
 
 	// Verify orphan file is gone
-	f, err := cleanedRepos.Files.GetByPath(ctx, file.Path)
+	f, err := cleanedRepos.Files.GetByPath(ctx, file.Path.String())
 	if err != nil {
 		t.Fatalf("failed to check file: %v", err)
 	}
@@ -137,7 +137,7 @@ func TestCleanSnapshotDBEmptySnapshot(t *testing.T) {
 	}
 
 	// Verify orphan chunk is gone
-	c, err := cleanedRepos.Chunks.GetByHash(ctx, chunk.ChunkHash)
+	c, err := cleanedRepos.Chunks.GetByHash(ctx, chunk.ChunkHash.String())
 	if err != nil {
 		t.Fatalf("failed to check chunk: %v", err)
 	}